Interplay between cytosolic dopamine, calcium, and alpha-synuclein causes selective death of substantia nigra neurons.
|Title||Interplay between cytosolic dopamine, calcium, and alpha-synuclein causes selective death of substantia nigra neurons.|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Mosharov, EV, Larsen KE, Kanter E, Phillips KA, Wilson K, Schmitz Y, Krantz DE, Kobayashi K, Edwards RH, Sulzer D|
|Date Published||2009 Apr 30|
|Keywords||alpha-Synuclein, Animals, Animals, Newborn, Calcium, Calcium Channel Blockers, Calcium-Binding Protein, Vitamin D-Dependent, Cell Death, Cytosol, Dopamine, Dopamine Agents, Dose-Response Relationship, Drug, Electrochemistry, Enzyme Inhibitors, Gene Expression Regulation, Green Fluorescent Proteins, Humans, Hydrazines, Levodopa, Mice, Mice, Inbred C57BL, Mice, Transgenic, Neurons, Rats, Rats, Sprague-Dawley, substantia nigra, Time Factors, Tyrosine 3-Monooxygenase, Vesicular Monoamine Transport Proteins|
The basis for selective death of specific neuronal populations in neurodegenerative diseases remains unclear. Parkinson's disease (PD) is a synucleinopathy characterized by a preferential loss of dopaminergic neurons in the substantia nigra (SN), whereas neurons of the ventral tegmental area (VTA) are spared. Using intracellular patch electrochemistry to directly measure cytosolic dopamine (DA(cyt)) in cultured midbrain neurons, we confirm that elevated DA(cyt) and its metabolites are neurotoxic and that genetic and pharmacological interventions that decrease DA(cyt) provide neuroprotection. L-DOPA increased DA(cyt) in SN neurons to levels 2- to 3-fold higher than in VTA neurons, a response dependent on dihydropyridine-sensitive Ca2+ channels, resulting in greater susceptibility of SN neurons to L-DOPA-induced neurotoxicity. DA(cyt) was not altered by alpha-synuclein deletion, although dopaminergic neurons lacking alpha-synuclein were resistant to L-DOPA-induced cell death. Thus, an interaction between Ca2+, DA(cyt), and alpha-synuclein may underlie the susceptibility of SN neurons in PD, suggesting multiple therapeutic targets.